The kidney is a highly vascularized organ. This makes kidney surgery difficult because any incisions into the organ tend to cause large amounts of bleeding. During laparoscopic surgery blood flow to the kidney is often interrupted by clamping off the renal artery. During this time of blood flow deprivation, the kidney may easily become damaged by ischemia. Very significant damage can occur after thirty minutes of blood flow deprivation. Because of ischemic damage, surgery tends to be done as quickly as possible. To reduce the rate of ischemic damage, the kidney may be cooled before operating. Lowering the temperature of the organ reduces the rate at which ischemic damage is caused because it slows the local metabolic rate of the organ and reduces catabolic enzymic activity.
A number of disclosures exist that describe the cooling of organs prior to or during transportation for transplantation. Transfusion of cold saline into the kidney via the uterer or renal artery has been described, but neither technique appears to produce sufficient cooling of the cortex of the kidney to prevent ischemic damage. In order to avoid ischemic damage, the kidney parenchyma should preferably reach about 15° C., but these two current methods produce parenchymal temperatures of only about 21-24° C., insufficient to avoid damage. Additionally, injecting water through the renal artery may lead to renal artery injury and thrombosis. Another solution employs a tubular “Endocatch II” bag (United States Surgical, Norwalk, Conn.) placed around the kidney and through which coolant (an ice slush) is pumped. Using this technique, Touijer et al have been able to produce parenchymal temperatures of between 5° C. and 19° C. within 10 minutes. But in order to perform surgery, the bag must be removed. The kidney quickly warms, allowing ischemia to occur.
A number of patent disclosures describe relevant methods and devices for cooling organs. Many of these disclosures, however, relate to cooling organs during transportation after the organs have been removed from the body for transplantation.
U.S. Pat. No. 4,008,754 describes a method of organ preservation comprising rinsing the organ with an inert gas until it is free of water and blood. The vascular system is thus filled with the inert gas or gas and the organ is cooled in an inert gas atmosphere to a temperature below minus 100° C.
U.S. Pat. No. 4,471,629 describes a method of freezing and transplanting a kidney. This method uses the successive step of infusing pressurized chilled helium into the renal artery while progressively and rapidly cooling the kidney located on a support of a container that is not immersed but surrounded by a body of liquid nitrogen. A further step includes the thawing of the frozen kidney by application of infrared radiation to the kidney within a confined area while continuously rotating the kidney for uniform thawing, much like a traditional rotisserie.
U.S. Pat. No. 4,473,637 describes a system for processing an organ such as a kidney so as to render it suitable for storage, shipment and eventual transplantation. After its removal from a donor, the organ is cradled in a net suspended within a basin. A preservative fluid initially at normal blood temperatures progressively cooled to avoid thermal shock, the fluid being pumped through the organ to flush out its natural fluids. The pumping action is such as to simulate that of the heart and its associated circulatory system. The exterior of the organ is chilled by simultaneously introducing the preservative fluid into the basin. After this chilling procedure is completed, the cradle carrying the cooled organ is transferred to a basin disposed in a thermally-insulated shipping box which is then filled with chilled preservative fluid and maintained at a desired low temperature level by an associated refrigeration unit. Just prior to transplantation, the cradle carrying the organ is removed from the box and the organ is again flushed, using the same procedure as in chilling but in reverse, the preservative fluid being raised to a temperature level close to normal blood temperature. Upon completion of this procedure, the organ is in condition for transplantation.
U.S. Pat. No. 6,692,519 describes methods for preventing hypoxic damage to a potentially transplantable organ prior to explanation of that organ or tissue from the body of a donor. The methods comprise placing a heat exchange apparatus in the vasculature of the donor or recipient and using that heat exchange apparatus to cool at least a portion of the body of the donor or recipient to a temperature below 36° C.
U.S. Pat. No. 5,723,282 describes a Method for preparing organs for cryopreservation through the introduction of a chilled liquid into the organ to reduce the temperature of the organ to as low as minus 5° C.
Prior to the present disclosure, no method or device has existed to cool the kidney in situ, during laparoscopic surgery, providing adequate cooling and without damaging the kidney.